The Protection Of Dexmedetomidine Against The Lung Injury Of Thoracoscopi Thymectomy In Patients With Myasthenia Gravis

Objective:To evaluate the lung protection effect of the different doses of dexmedetomidine?DEX?in patients with myasthenia gravis undergoing thora-coscopic thymectomy surgery.Method:Forty patients with myasthenia gravis undergoing thora-coscopic thymectomy surgery were selected:the American Society of anesthe-siologists?ASA?grade I^II,age 18⁶5 years old,male or female,gravis typical clinical manifestations,change of neostigmine test positive or EMG,except for other neuromuscular diseases,while imaging showed thymic hyperplasia or manifestations of thymoma.After signing the informed consent,According to the difference in the rate of continuous pump entry in DEX,the study subjects were randomly divided into 4 groups?n=10?:group D1:0.2?g/?kg·h?DEX,group D2:0.4?g/?kg·h?DEX,group D3:0.6?g/?kg·h?DEX and group C?saline control group?.DEX?1?g/kg?was infused intravenously within 10 min before anesthesia induction in all DEX groups,and then was infused intravenously at 0.2?g/?kg·h?,0.4?g/?kg·h?and0.6?g/?kg·h?respectively in group D1,group D2 and group D3 for anesthesia maintenance until the operation finished,group C was controlled by saline.Anesthesia was maintained with propofol at the rate of 3⁵mg/?kg·h?and remifentanil at the rate of 0.1⁰.2?g/?kg·min?.Intermittent intravenous injection of cisatracurium maintained muscle relaxation.And the value of BIS was maintained between 40⁶0.The patients in each group were recorded the mean arterial pressure?MAP?and heart rate?HR?before anesthesia?T0?,at moment after intubation?T1?,at moment of one lung ventilation for 30minutes?T2?,at moment of one lung ventilation for 90 minutes?T3?and at moment of 2 hours after operation?T4?.The Pa O2 and PaCO2 were recorded and calculated the alveolar arterial oxygen difference[P?A-a?O2]and oxygenation index?PaO₂/Fi O₂?at T0,T2,T3 and T4.The peak airway pressure?Ppeak?were monitored and recorded at T1,T2,T3 and T4.5 ml venous blood in each group at T0,T1,T2,T3 and T4 was taken into a test tube.The concentration of TNF-?and IL-6 protein of the serum was determined by ELISA.Results:1.hemodynamic indexHR:Compared with the group C,the HR decreased significantly in group D2 at T4?P<0.05?,the HR decreased significantly in group D3 at T3 and T4?P<0.05?.Compared with the group D1,the HR decreased significantly in group D2 at T4?P<0.05?,the HR decreased significantly in group D3 at T3and T4?P<0.05?.Compared with the group D2,the HR decreased in group D3 at T3 and T4?P<0.05?.Compared with T0,the HR decreased significantly in group D3 at T3?P<0.05?,the HR increased significantly in group C and group D1 at T4?P<0.05?.there were 3 cases with HR<60times/min in group D3.MAP:Compared with the group C,the MAP decreased significantly in group D2 at T4?P<0.05?,the MAP decreased significantly in group D3 at T3and T4?P<0.05?.Compared with the group D1,the MAP decreased significantly in group D2 at T4?P<0.05?,the MAP decreased significantly in group D3 at T2,T3 and T4?P<0.05?.Compared with the group D2,the MAP decreased in group D3 at T2,T3 and T4?P<0.05?.Compared with T0,the MAP decreased significantly in group D3 at T2,T3 and T4?P<0.05?,the MAP increased significantly in group C and group D1 at T4?P<0.05?.there were 2 cases with MAP<70mmHg in group D3.2.blood gas analysisP?A-a?O₂:Compared with the group C,the P?A-a?O₂ decreased signific-antly in D1,D2 and group D3 at T2,T3 and T4?P<0.05?.Compared with group D1,the P?A-a?O₂ decreased significantly in D2 and group D3 at T4?P<0.05?.Compared with group D2,there was no difference in group D3 at each time point?P>0.05?Compared with T0,the P?A-a?O₂ increased significantly in each group at each time points?P<0.05?.PaO₂/FiO₂:Compared with the group C,the PaO₂/FiO₂ increased signif-icantly in D1,D2 and group D3 at T2,T3 and T4?P<0.05?.Compared with group D1,the PaO₂/FiO₂ increased significantly in D2 and group D3 at T3and T4?P<0.05?.Compared with group D2,there was no difference in group D3 at each time point?P>0.05?.Compared with T0,the PaO₂/FiO₂ decreased significantly in each group at each time point?P<0.05?.3.mechanical mechanical indexes of lungPpeak:Compared with the group C,the Ppeak decreased significantly in D2 and group D3 at each time point?P<0.05?.Compared with the group D1,the Ppeak of group D3 decreased significantly at T2?P<0.05?.Compared with group D2,there was no difference in group D3 at each time point?P>0.05?.Compared with T1,the Ppeak decreased significantly in each group at each time point?P<0.05?.4.inflammatory mediatorsTNF-?:Compared with the group C,the TNF-?decreased significantly in group D1 at T1?P<0.05?,the TNF-?decreased significantlyin in D2 and group D3 at T1,T2,T3 and T4?P<0.05?.Compared with group D1,the TNF-?decreased significantly in group D2 at T3 and T4?P<0.05?,so did in group D3 at T2,T3 and T4?P<0.05?.Compared with group D2,there was no difference in group D3 at each time point?P>0.05?.Compared with T0,the TNF-?increased significantly in each group at each time point?P<0.05?.IL-6:Compared with the group C,the IL-6 decreased significantly in group D1 at T1,T2 and T3?P<0.05?,the IL-6 decreased significantly in D2and group D3 at T1,T2,T3 and T4?P<0.05?.Compared with group D1,the IL-6 decreased significantly in D2 and group D3 at T3 and T4?P<0.05?.Compared with group D2,there was no difference in group D3 at each time point?P>0.05?.Compared with T0,the IL-6 increased significantly in each group at each time point?P<0.05?.Conclusions:DEX plays an important lung protection in patients with myasthenia gravis undergoing thoracoscopic surgery,...